Koch carbonylation reaction

Koch carbonylation reaction (Koch-Haaf carbonylation reaction)... 

Olefins are carbonylated in concentrated sulfuric acid at moderate temperatures (0—40°C) and low pressures with formic acid, which serves as the source of carbon monoxide (Koch-Haaf reaction) (187). Liquid hydrogen fluoride, preferably in the presence of boron trifluoride, is an equally good catalyst and solvent system (see Carboxylic acids). 

Figure 22-8 Some carbonylation reactions. Reppe reactions involve CO + H20 or CO + ROH. Koch reactions involve CO + H20 in strongly acidic solution. Oxidative carbonylations may involve 02, NO, or ROOR.

In the Koch-Haaf reaction, a superacid/CO mixture leads to carbonylation of the alkane. A variety of products were obtained, e.g. BuKTOaH, IVCHCOMe and Pr CHaCOBu, from isobutane using this product. Usually the method is only useful for alkanes containing a tertiary C—H bond, but Sommer has introduced a modification that sdlows secondary C—H bonds to be functionalized, although only with 4% conversion (equation 3S). ... 

The acid-catalyzed hydrocarboxylation of alkenes (the Koch reaction) can be performed in a number of ways. In one method, the alkene is treated with carbon monoxide and water at 100-350°C and 500-1000-atm pressure with a mineral acid catalyst. However, the reaction can also be performed under milder conditions. If the alkene is first treated with CO and catalyst and then water added, the reaction can be accomplished at 0-50°C and 1-100 atm. If formic acid is used as the source of both the CO and the water, the reaction can be carried out at room temperature and atmospheric pressure.The formic acid procedure is called the Koch-Haaf reaction (the Koch-Haaf reaction can also be applied to alcohols, see 10-77). Nearly all alkenes can be hydrocarboxylated by one or more of these procedures. However, conjugated dienes are polymerized instead. Hydrocarboxylation can also be accomplished under mild conditions (160°C and 50 atm) by the use of nickel carbonyl as catalyst. Acid catalysts are used along with the nickel carbonyl, but basic catalysts can also be employed. Other metallic salts and complexes can be used, sometimes with variations in the reaction procedure, including palladium, platinum, and rhodium catalysts. The Ni(CO)4-catalyzed oxidative carbonylation with CO and water as a nucleophile is often called Reppe carbonylationP The toxic nature of nickel... 

The first oxidative carbonylation reactions (cf. Section 2.1.2.5) with methane used superacid catalysts to perform the carbonylation in a Koch-type reaction which involved protolytic oxidation of methane to the methyl cation (eq. (29) [137]) ... 

An interesting but rather unusual reaction involves the direct carbonylation of carbocations to carboxylic acid derivatives. Carbenium ions can be generated from alkenes or alkanes in strong acidic media. Thus, tertiary carboxylic acids can be produced from C4 or higher alkenes Koch-Haaf reaction) [39] (e.g., eq. (8)). Interestingly, Koch carbonylations are known to be catalyzed by copper or silver cations [40]. 

Commercial petrochemical processes using syngas or carbon monoxide are based on four principal classes of reactions phosgenation, Reppe chemistry, hydroformylations, and Koch carbonylations. Phosgenation is a key step in the manufacture of polyurethanes, polycarbonates, and monoisocyanates. Reppe chemistry is the basis for acetic acid and acetic anhydride production as well as formic acid and methyl methacrylate synthesis. Hydroformylations utilize syngas in the oxo synthesis to make a wide variety of aldehydes and long-chain alcohols. The fourth class of reactions are Koch carbonylations. Koch carbonylations are used commercially to produce neo acids which are specialty products that serve markets similar to 0X0 alcohols. 

The term carbonylation was first used by W.Reppe while working with syngas and carbon monoxide chemistry at BASF during the 1930s and 1940s. Carbonylations are catalytic reactions in which carbon monoxide, alone or with other compounds, is incorporated in an organic substrate. There are three general types of carbonylation reactions Reppe reactions, hydroformylations, and Koch carbonylations. 

Hydroformylation is the reaction of carbon monoxide and hydrogen with olefins to produce aldehydes and derivative alcohols. It is also known as 0X0 chemistry and the alcohol products produced by this method are known as 0X0 alcohols. Of all three types of carbon monoxide reactions, Reppe reactions, Koch carbonylations, and hydroformylations, oxo chemistry currently has the greatest commercial importance. An extremely broad range of products and end use markets are served by the aldehydes, alcohols, and derivatives produced by hydroformylation. The list of products shown in Table 6 illustrates the range of oxo chemical products. 

The carbonylation reaction on the present system is most likely interpreted to be the carbonylation of methyl carbenium ion, as postulated for the Koch reaction (11). Copper(II) ion that was incorporated into the zeolites by ion exchange accelerates the carbonylation. The copper ion did not change the product pattern. The copper(II) ion on the zeolite might be reduced by methanol or carbon monoxide to copper(I) ion under reaction conditions. The copper(I) ion has been known to react easily with carbon monoxide to form Cu(CO)n (S < n < 4), which is an active carbonylation reagent for formaldehyde, n-olefins, and alcohols (85). 

The mechanism of this reaction may be similar to that of the classical Koch reaction (11) and promoting role of copper consists of coordination of CO by Cu(I) species (11,85,90). The promoting role of copper, however, suggests that a high density of acidic sites may be inimical to the carbonylation reaction, since metal exchange is known to reduce significantly the number of Brpnsted acid sites present in zeolites. 

Hydroformylation, ring closure reactions and the Koch acid syntheses may be carried out in autoclaves made from stainless steel. If the formation of iron pentacarbonyl has to be completely avoided, silver or copper lined autoclaves may be used. If hydrogen halides or hydrogen halide generating compounds are used, which e.g., is the case in the Reppe carbonylation reactions, stainless steel autoclaves cannot be used due to corrosion. HasteUoy B or Hastelloy C should be used instead. 

The isolation of saturated and unsaturated acetic acid derivatives in the manganese(m) acetate oxidation of olefins has been reported earlier examples of this oxidation led solely to y-lactones. A one-step synthesis of aeo-di-carboxylic acid diesters has been reported, based on Kolbe electrolysis of oxalic and malonic half-esters in the presence of olefins, and is exemplified in Scheme 2. As part of a study of insect hormone activity, Kolbe electrolysis has been utilized in the preparation of aj9-unsaturated Cj4—Cj7 acid esters with a terminal quaternary alkyl group. The utility of liquid hydrogen fluoride in the Koch carbonylation of olefins has been descried, as has a general study of this reaction. ... 

Addic ILs promote the carbonylation of tertiary alcohols with CO (Koch carbonyl-ation. Scheme 6.6) [66]. The reaction is performed in a biphasic mode, using decane as a second phase, therefore allowing the separation of reaction products. The pivalic acid yield reaches 23% at 150 °C and 80 bar CO. 

Propylene-Based Routes. The strong acid-catalyzed carbonylation of propylene [115-07-1] to isobutyric acid (Koch reaction) followed by oxidative dehydration to methacrylic acid has been extensively studied since the 1960s. The principal side reaction in the Koch reaction is the formation of oligomers of propylene. Increasing yields of methacrylic acid in the oxydehydration step is the current focus of research. Isobutyric acid may also be obtained via the oxidation of isobutyraldehyde, which is available from the hydroformylation of propylene. The -butyraldehyde isomer that is formed in the hydroformylation must be separated. 

Carbonylation, or the Koch reaction, can be represented by the same equation as for hydrocarboxylation. The catalyst is H2SO4. A mixture of C-19 dicarboxyhc acids results due to extensive isomerization of the double bond. Methyl-branched isomers are formed by rearrangement of the intermediate carbonium ions. Reaction of oleic acid with carbon monoxide at 4.6 MPa (45 atm) using 97% sulfuric acid gives an 83% yield of the C-19 dicarboxyhc acid (82). Further optimization of the reaction has been reported along with physical data of the various C-19 dibasic acids produced. The mixture of C-19 acids was found to contain approximately 25% secondary carboxyl and 75% tertiary carboxyl groups. As expected, the tertiary carboxyl was found to be very difficult to esterify (80,83). 

The two main reasons for studying the reversible reaction (3) were (a) to complete the picture of the Koch reaction in terms of quantitative information and (b) to set up a scale of reactivity towards a neutral nucleophile for carbonium ions of different structure. The first item is important from a practical point of view because there are reactions competing with the carbonylation step (3), which can be divided into intramolecular and intermolecular processes. Rearrangement of the intermediate alkylcarbonium ion, e.g. 

By in situ MAS NMR spectroscopy, the Koch reaction was also observed upon co-adsorption of butyl alcohols (tert-butyl, isobutyl, and -butyl) and carbon monoxide or of olefins (Ao-butylene and 1-octene), carbon monoxide, and water on HZSM-5 (Ksi/ Ai — 49) under mild conditions (87,88). Under the same conditions, but in the absence of water (89), it was shown that ethylene, isobutylene, and 1-octene undergo the Friedel-Crafts acylation (90) to form unsaturated ketones and stable cyclic five-membered ring carboxonium ions instead of carboxylic acids. Carbonylation of benzene by the direct reaction of benzene and carbon monoxide on solid catalysts was reported by Clingenpeel et al. (91,92). By C MAS NMR spectroscopy, the formation of benzoic acid (178 ppm) and benzaldehyde (206 ppm) was observed on zeolite HY (91), AlC -doped HY (91), and sulfated zirconia (SZA) (92). 

The acid-catalyzed hydrocarboxylation of an alkene is known as the Koch Reaction. When the source of both the CO and the H20 is formic acid, the process is called the Koch-Haaf Carbonylation. 

The preparation of acetic acid represents a special case. Olah and coworkers as well as Hogeveen and coworkers have demonstrated that CO can react with methane under superacidic conditions, giving the acetyl cation and by subsequent quenching acetic acid or its derivatives (see Section 7.2.3). Monosubstituted methanes, such as methyl alcohol (or dimethyl ether), can be carbonylated to acetic acid.115 Similarly, methyl halides undergo acid-catalyzed carbonylation.115,116 Whereas the acid-catalyzed reactions can be considered as analogs of the Koch reaction, an efficient Rh-catalyzed carbonylation of methyl alcohol in the presence of iodine (thus in situ forming methyl iodide) was developed by Monsanto and became the dominant industrial process (see Section 7.2.4). 

Copper(I) carbonyls in the presence of H2S04 (>85%) catalyze the carbonylation of alcohols under ambient conditions (128). In this case, yields of up to 80% have been reported. The necessity of such high acid concentrations suggest that the chemistry involved may be described as a modified Koch reaction ... 

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